a) Field of the Invention
The present invention is directed to an arrangement for generating a variable illumination and irradiation for diagnosis and therapy, particularly for the human eye, and to a method for the application thereof. The object illuminated by the variable illumination can be an artificial object or biological tissue. However, with respect to the eye, it is also possible to irradiate other parts of the eye besides the lens, such as the cornea, retina or fundus. In particular, the invention can be used for fine adjustment of photosensitive plastics introduced into the eye (according to WO 00/41650 and WO 01/71411). With plastics of this type, the irradiation excites polymerization processes that result in irreversible chemical changes in the substance. The index of refraction, geometric shape and/or transmission behavior for the visible useful radiation and the geometric shape of the plastic body can be changed in a defined manner by these processes. In this way, it is possible to improve defective vision.
b) Description of the Related Art
Patents WO 00/41650 and WO 01/71411 describe lenses, particularly intraocular lenses (IOL) in which polymerization of a polymer matrix contained in the lens is excited by irradiation and the index of refraction or the shape of the entire lens can be changed in this way. With implanted IOLs, the problem exists that in approximately 50% of patients an acceptable visual acuity can be achieved only through additional corrective measures such as eyeglasses or contact lenses. This is the result, in part, of errors in eye measurements, deviations in the positioning of the IOL and/or is due to the healing process. With the described IOLs, a correction of the IOL which is already implanted is made possible through directed irradiation by adapting to the actual conditions through changes in the index of refraction, the transmission characteristics or the optically active shape. The irradiation of the IOL for exciting the polymerization process is preferably effected by means of laser sources or lamps emitting a high UV component of the light. For this purpose, an He/Cd laser or an Xe/Hg lamp is used as the irradiation source. Illumination structures which may possibly be required are generally produced by means of mechanical diaphragms and/or filters.
However, there are disadvantages to arrangements of the kind described above in that the supply of patterns is limited by fixed diaphragms, there is no possibility of intensity distribution within the diaphragm patterns, and dynamic processes can be realized, at best, through manual switching and, therefore, hardly at all. Moreover, the generated illumination patterns can not be adapted to individual findings and are not adaptive or suitable for online regulation.
199 43 735 A1 describes a method and a device for directed irradiation of an eye by means of light from the UV-A and/or visible near infrared wavelength range. The irradiation brings about irreversible chemical changes in the eye lens substance which result in a change in the index of refraction and/or in the transmission characteristics for the visible useful radiation and which accordingly make it possible to improve defective vision. Successful treatment requires that the distribution of the refractive power of the eye being treated is determined over the most closely-knit, fullest area possible. The refractive power distribution desired after treatment and the data for the irradiation that are required for this purpose are determined from these values. Inevitably, however, the eyeball must usually be fixated for the duration of the treatment.
Patents WO 02/26121 and WO 02/31576 describe solutions for the irradiation of optical lenses or lens systems made from photosensitive plastics (according to WO 00/41650 and WO 01/71411) which are already implanted in the eye as intraocular lenses. In this solution, the irradiation patterns in question are determined by a computer program based on a wavefront analysis that is carried out beforehand. In addition to a diagnostic element for monitoring before, during and after irradiation, a surgical microscope is provided for additional visual observation. However, this solution has disadvantageous results in that there is only one fixating light for the patient. Experience has shown that it is difficult for the patient to concentrate on a stationary fixating light for the duration of treatment, so that movements of the eye can nevertheless occur.
DE 198 12 050 A1 describes a method and an arrangement for illumination in an ophthalmic microscope. A large variety of light mark geometries is generated by means of optoelectronic components and projected on the anterior portion or on the fundus of the eye. This solution is used for general examination of the eye. An arrangement for generating section images in transparent media is provided in DE 101 55 464.8, which has not yet been published. An ophthalmological examination device which enables a perimetric examination as well as a general eye examination has also not been published (DE 101 51 314.3). The solutions contained in both of these references likewise provide for the use of optoelectronic components for generating illumination marks and illumination patterns.